For decades, none but a few privileged -- and highly trained -- individuals could dare dream of traveling beyond Earth's orbit. All that's set to change as Richard Branson brings space exploration to the (mega-rich) masses.

In April, Virgin Galactic -- a subsidiary of Branson's Virgin Group -- hit a milestone. The rocket motor the company had been testing on the ground was fitted into SpaceShip Two, the spacecraft that, from next year onwards, will bring space travel to the general public.

"We lit the rocket motor for the first time in the air and the spaceship went through the sound barrier," recalls Stephen Attenborough, Virgin Galactic's commercial director.

"It was a hugely significant milestone for us, and in many ways, the last big piece of the jigsaw."

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"It's still about 1% of the price you would have needed to pay to go to space as a private citizen before now," maintains Attenborough. Indeed, in the past, the privilege cost civilians a fair share. When Dennis Tito, the world's first "space tourist" bought a seat aboard a Russian Soyuz spacecraft in 2001, it allegedly cost him nearly $20 million.

Though flights won't commence until next year at the earliest, Virgin Galactic has already sold 640 seats to space enthusiasts the world over. For some, the cost is negligible. Others, though, have taken second mortgages on their homes to pay for the tickets.

So what does $250,000 buy you?

The experience starts with three days of training at Spaceport America in New Mexico.

"There's a lot to do with getting you psychologically prepared for a trip that is absolutely about sensory overload," says Attenborough.

The flight itself accommodates six passengers, lasts two and a half hours, and culminates with congratulatory champagne at the spaceport. Space travelers get to leave their seats to experience several minutes of zero-gravity, and perhaps the most iconic view ever afforded mankind.

"Ultimately, you get memories to last a lifetime -- a trip I think will just blow people away. When talking to professional astronauts of the past, they don't talk about (their experiences) for a day or a year, they talk about it for the rest of their lives."

Still, there are many enthusiasts eager to see the price drop, not the least of whom is American astronaut Buzz Aldrin. Aldrin recalls the first time he heard the concept of private space travel debated in a meeting room 25 years ago.

"Somebody said, 'How are we going to select (who gets to fly to space)?' Someone in the back of the room said, 'How about a lottery?' Man, my ears perked up at that, and I became a devotee of a lottery to select people."

The civilian lottery is the basis of Aldrin's non-profit, SpaceShare.

"I wasn't interested in a big pay-off of the profit made. I was interested in exposing space to a large number of people," he says.

Attenborough himself is eager to see the price drop.

"This is not just a business for Virgin. It's about the creation of a new and important industry that is going to transform space access. One of the byproducts of that is there will be competition, there will be economies of scale, and we should see the price go down," he says.

"Hopefully there will be a large, thriving, vibrant industry that will make it possible for most people to go into space in my lifetime."